Ornamental design for motorcycle



FIG. 1 is a left side/front perspective view of a motorcycle showing our new design;

FIG. 2 is a right side elevational view thereof;

FIG. 3 is a left side elevational view thereof;

FIG. 4 is a front elevational view thereof; and,

FIG. 5 is a rear elevational view thereof. 

The ornamental design for a motorcycle, as shown. 